diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index b5aa8cd6e7c5b..5cfcfe98faae3 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -878,6 +878,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             format!("impl {}", all_bounds_str),
             Applicability::MaybeIncorrect,
         );
+        err.note("the caller chooses the value of a type parameter");
     }
 
     pub(in super::super) fn suggest_missing_break_or_return_expr(